Assembly for converting a drill press to a circular saw

ABSTRACT

Attachments are provided to convert a pivotal-column drill press to a circular saw by mounting a work table on the support table of the drill press, installing a saw and arbor in the drill press chuck, and mounting saw guards on an overhanging portion of the work table opposite a slot receiving the saw blade.

United States Patent Morse Apr. 2, 1974 ASSEMBLY FOR CONVERTING A DRILL2,963,057 12/1960 Morse 144 c RE o A C RC SAW 3,060,979 l0/l962 Hanvint. 83/4772 2,822,836 2/1958 Horstmann ct al. 144/35 A X Inventor: GlennMorse, 321 Fountain 2,095,330 10/:937 'fii' eih'." ..83/47s x GrandRapids, Mich. 49503 [22] Filed: Aug. 28, 1972 Primary ExaminerAndrew R..luhasz Assistant ExaminerW. D. Bray [21] Appl' 284,424 Attorney, Agent,or Firm-Glenn B. Morse [52] US. Cl. 144/1 C, 144/35 A, 83/4772,

83/478, 83/698, 408/20 [57] ABSTRACT [51] Int. Cl. B27c l/l4 [58] Fieldof Search 83/478 544-546 Altachmems are pmvded m come" 3 p'votal'colum"83/698 477 2 14455 A 1 l C 1 drill press to a circular saw by mounting awork table l 1 248/12 6 on the support table of the drill press,installing a saw and arbor in the drill press chuck, and mounting saw[56] References Cited guards on an overhanging portion of the work tableopposite a slot receiving the saw blade. UNITED STATES PATENTS 3,709,622l/ 1973 Morse 144/1 C X 4 Claims, 7 Drawing Figures ll! 27 Ill 1 "ll lIll 79 I l l| ASSEMBLY FOR CONVERTING A DRILL PRESS TO A CIRCULAR SAWBACKGROUND OF THE INVENTION The US. Pat. No. 2,963,057 describes a drillpress having a pivotal joint in the column, in contrast to the usualfixed column extending from the base directly to the power head. Thepivotal arrangement permits the front column (carrying the power head)to be rotated from the vertical to a horizontal position, in which itbecomes capable of a variety of functions described in that patent. Inone of these, the support table of the drill press is rotated to ahorizontal position parallel to the front column, and a circular sawblade is held in an arbor carried by the drill press chuck. The supporttable of the drill press is used directly as a work table for theresulting circular saw, with the saw projecting through a slot in thedrill press table.

This arrangement has resulted in serious problems in providingsufficient safety features to render the assembly usable by relativelyunskilled workers. In addition to the usual problems associated withprotecting the worker against the portion of the saw blade above thework table, the entirety of the blade below the work table is alsoexposed. To complicate the matter further, the portion underneath thetable is not directly visible to the operator, and it becomes all tooeasy to have the,

clothing or his hands engaged with the rotating saw blade. A furtherproblem has been the consequences of accidental disengagement of thearbor from the chuck, or the saw blade from the arbor, which will resultin suddenly freeing the spinning saw blade in a position where thecontinued rotation will tend to induce lateral movement at a tremendousvelocity with resulting danger. The installation of appropriate sawguards for the upper and lower portions of the rotating blade haveproduced design problems which have not had a readily apparent solution.While it is conceivable that a guard structure could be secured to theunderside of the table as an item added to the arrangement shown in US.Pat. No. 2,963,057, such an arrangement tends to result in thelimitation in the usable diameter of the saw blade, and to seriousproblems in interference when the saw blade must necessarily operate ina position so close to the solid metal forming the drill press table.

Another problem has been the appropriate mounting of a splitter plate (athin plate which engages the cut made by the saw) so that it canfunction properly as a support for an upper saw guard assembly. The mostdesirable point of placement of the splitter support falls in an areaoutside the dimensions of an ordinary drill press work table, and it isundesirable to provide special table structure for particularattachments of this kind. The relative alignment of the guard componentshas also proved to be a problem, as it is highly undesirable to requireclose tolerances in the equipment of this nature, which is necessarilyinstalled and removed by the user on frequent occasions.

SUMMARY OF THE INVENTION A very practical solution to the above problemhas appeared in an assembly in. which a panel forming a work table forthe circular saw is secured to the drill press support table, and sawguards are mounted opposite a blade-receiving slot in a portion of thiswork table which overhangs the margin of the drill press support table.This panel forms a unifying frame for a subassembly in which the upperand lower saw guard components are accurately aligned, and are removablefrom the basic machine as a unit. The table is of a material which isreadily cuttable by the saw, which eliminates the danger of possibleinterference on accidental displacement of the saw from its normaloperating position. A modification to the feed mechanism of aconventional drill press is provided to give an extended plane ofclearance at the level of the top of the work table, so that largesheets of plywood or other such items can be handled by the saw.

DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of a drillpress having a jointed column assembly, with the front column in thevertical position.

FIG. 2 is a perspective view on an enlarged scale over that of FIG. 1,showing the front column and power head in a horizontal position, andwith the components of the circular saw attachment assembly fullyinstalled.

FIG. 3 is a perspective view of an intermediate step in the installationof the circular saw assembly, from the underside of the table. The lowersaw guard has been removed, and the saw blade is shown displaced fromoperating position.

FIG. 4 is a perspective view from the rear and below the installationshown in FIG. 2, on approximately the scale of FIG. 3.

FIG. 5 is a perspective view from the front and above, illustrating therelationship of the table, the upper saw guard, and the guide fence.

FIG. 6 is a rear view of the lower saw guard assembly in perspective.

FIG. 7 is a view of the arbor assembly held in the drill press chuck forthe support and placement of the saw blade.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to FIG. 1, the rearcolumn 10 is fixed to the base 11. The fulcrum member 12 is secured tothe top of the fixed rear column 10, and supports a shaft secured to thecolumn-clamping member 13. A nut 14 at the opposite extremity of thisshaft can be tightened or loosened to vary the resistance to rotationbetween the clamping member 13 and the fixed pedestal assembly includingthe fulcrum member 12, the rear column 10, and the base 11.

The front column 15 is slidably and rotatively received in the clampingmember 13, and clamp bolt 16 can be adjusted to constrict the clamp 13about the column and secure the axial and rotative position of thecolumn with respect to the clamping member 13. The power head assemblyindicated generally at 17 is conventional, except for modification ofthe quill feed shaft 18. This shaft is controlled by the handle 19 toadvance the spindle axially so that a drill held in the chuck 20 canadvance into the piece being drilled, which is usually supported on thetable 21. In the illustrated embodiment, the table 21 has an off-set arm22 pivotally connected to a table bracket 23 on a conventional bolt 23a,and locked by a locking bolt 23b (refer to FIG. 2). The bracket 23 isrotatively and axially slidable on the column 15 under the control ofthe clamping bolt 24.

Prior to the installation of the components of the circular sawassembly, the front column is rotated into the horizontal position shownin FIG. 2. It is preferable that the machine be provided with aset-screw in the fulcrum member 12 to engage the pivot shaft, and lockthe assembly in the FIG. 2 position. It is also preferable that thetable bracket 23 be provided with a coupling pin 26 for engagement witha similarly-shaped recess in the axially opposite end of the clampingmember 13 so that the bracket 23, on being moved axially toward theclamping member 13, can become rotatively interengaged with it and thusassure that the table 21 remains in the horizontal position while thepower head 17 is free to rotate about the axis of the column 15 when theclamp bolt 16 (and also the clamp bolt 24) are loosened. This couplingsystem is described and claimed in my application for US. patent, Ser.No. 284,4l7 filed with the present application.

The first step in the installation of the circular saw assembly is theplacement of the saw table panel 27 on the top surface of the drillpress support table 21. The securing of the panel in position ispreferably accomplished through the use of flat-headed screws as shownat 28 and 29 in FIG. 5 traversing the work table 27 and engaging tappedholes as shown at 30 in the drill press support table 21. The heads ofthese screws are received in the usual beveled recesses so that theworking surface of the table 27 is unobstructed. The relative lo cationof the holes receiving the screws 28 and 29, and the tapped holes 30, issuch that the saw-receiving slot 31 in the table 27 is in a portion ofthe table panel overhanging the adjacent edge 32 of the drill presssupport table 21. With the table panel 27 in this position, the handle19 of the drill press feed assembly can be actuated (on loosening of theclamp handle 33) to move the spindle assembly carrying the chuck 20 tothe right. Prior to making this adjustment, the arbor 34 is installed inthe chuck 20. The enlarged portion 35 has a shoulder 36 at the rightend, as viewed in FIG. 7, adapted to receive the conventional centralopening of the saw blade 37 in closely-fitting relationship. The ring 38has a central recess capable of fitting over the projection 39 on thearbor to hold the saw 37 securely, regardless of the relative thicknessof the saw and the axial length of the projection 39. The bolt 40traverses the ring 38, and is in threaded engagement with the portion 35of the arbor. A pair of wrench flats as shown at 41 facilitates holdingthe arbor in position while the bolt 40 is tightened. When the saw blade37 has been installed on the arbor assembly, and the arbor in the chuck20, the handle 19 may be adjusted to place the saw directly opposite themiddle of the slot 31 in the work table 27. The clamp handle 33 is thentightened to secure the spindle assembly of the drill press in thisposition. The clamp bolt 16 in the clamp member 13 is then loosened sothat the power head can be swung upward to position the saw blade 37 atthe desired vertical position with respect to the top surface of thework table 27 The clamp bolts 16 and 24 are then tightened securely.

Before the machine can be considered safe for use, the lower saw guardunit shown in FIG. 6 should be installed. The housing 42 has the spacedside walls 43 and 44 separated by the peripheral walls 45 and 46. Anopening is preferably provided at 47 as a point of discharge forsawdust. The sidewall 43 has a slot 48 capable of receiving the portion35 of the arbor assembly shown in FIG. 7 in various vertical placementswith respect to the surface of the work table 27.

The front of the lower guard assembly is provided with a tab 49 having ahole 50 positioned to receive a bolt 51 traversing the work table 27.The tab 49 is secured preferably by the wing nut 52. The rear portion ofthe lower-guard is secured with rivets or spot welding to a bridgemember 53 provided with spaced hearing feet 54 and 55 having the holes56 and 57, respectively, disposed to receive the bolts 58 and 59traversing the work table 27. On tightening of the wing nuts 52, 60, and61, the lower guard unit is securely held in position. The bridge 53spans the slot 62 in the table 27 receiving the splitter plate 63, andthe effect of the bridge 53 is not only to hold the rear portion of theguard in position, but also to stabilize the portions of the table panel27 on the opposite side of the slot 62.

The splitter plate 63 has a flange 64 receiving the bolt and nutassembly 64 and 66 traversing the table panel 27 to hold the splitterplate 63 securely in position. This plate has the dual function of (a)maintaining the separation in the work piece on the opposite sides ofthe saw cut, and (b) supporting the upper saw guard 67. The frontportion of this guard straddles the slot 31 in the table 27 whichreceives the rotating saw blade 37. This forward portion is indicated at68, and has a U configuration in cross section. The front edges of thelegs of U are beveled as shown at 69, so that an oncoming board movingtoward the saw will elevate the guard 67 as the board is advanced. Therear portion of the guard 67 is-positioned by the presence of the flatportions 70 and 71 on opposite sides of the splitter plate 63. A rivet72 traverses these flat portions, and also traverses the inclined slot73 in the splitter plate. This slot is inclined upwardly and rearwardlyat approximately 10 degrees from the vertical, which has beenestablished by experiment to produce a very satisfactory raising andlowering movement of the guard 67 as a board passes underneath. Thisinclination induces the guard to swing downward on top of the surface ofthe board being sawed at an early stage in the movement of the boardthrough the saw, and also permits the guard to return to the positionshown on FIG. 5 after the board has passed beyond the guard assembly.The opposite portions 70 and 71 of the guard 67, together with the rivet72, are freely slidable with respect to the splitter plate 63, but witha minimum of clearance. The function of the splitter plate, togetherwith the relatively large bearing interengagement between the portions70 and 71 and the splitter plate, is to stabilize the positions of theguard 67 so that the opposite portions of the forward section 68 rest onthe opposite sides of the saw slot 31 in the work table 27.

An alternative installation procedure to the separate installation ofthe lower guard is to leave the lower guard mounted on the work table.The saw blade 37 can be slipped into the slot 31 from above and the sawsecured to the arbor 34 (before or after mounting the arbor in the chuck20) by manipulating the bolt 40 through an access hole (not shown) inthe wall 44 of the lower guard.

The drawings illustrate a very inexpensive form of alignment fence 74with the T head 74a. When the head 74a is pressed against the edge 75 ofthe table 27, the fence74 becomes parallel to the saw blade 37. A bolt76 engages the underside of the rail 73, and traverses the slot 77 inthe table 27. A washer 78 straddles the slot 77, and the wing nut 79 canbe tightened to secure the fence 74 in its adjusted position.

Where it is desirable to cut wide materials, such as plywood panels, itis often desirable to remove the fence from the table. This is donesimply by unscrewing the wing nut 79, and withdrawing the fence 74upwardly to the point of disengaging the bolt 76 from the slot 77. Theconventional power head assembly of the drill press provides aninterference problem due to the fact that the feed shaft 18 controlledby the handle 19 normally traverses the plane of the top of the table 27in all operating positions of the assembly. It is therefore desirable toprovide a disconnectable joint in this shaft at a position below thisplane. Referring to FIG. 4, the outer section 18a of the shaft isseparated from the inner section 18b at a point which places the outerend of the section 1812 below the level of the top of the table 22, asshown in FIG. 2, when the power head is tangent to this plane (byadjustment about the column axis). For this arrangement to provide fullyeffective clearance, the length of the offset table arm 22 should besuch that the top surface of the table 27 is at a distance above theaxis of the column which is greater than the minimum distance of thepower head from this axis. The outer section 18a is provided with anextension 80 received in a similarly-shaped recess in the end of thesection 18b, and bolt 81 traverses both the section 18b and theextension 80. Preferably, a flat area shown at 82 is machined on theouter surface of the section 18b to receive the head of the bolt 81. Thethumb nut 83 is conventional, and traverses the section 18a axially toprovide a clamping action against the handle 19 so that it can be placedin various positions radially with respect to the axis of rotation ofthe shaft 18.

I claim:

I. In combination with a machine having a column, a power head securedto said column and having a spindle carrying a chuck and rotatable on anaxis parallel to said column, a table bracket adjustably mounted on saidcolumn, a table adjustably secured to said bracket, and pivotal supportmeans for said column providing for placement of said column in selectedpositions between vertical and horizontal, said column being rotativelyadjustable about its own axis with respect to said pivotal supportmeans, a circular saw assembly comprising:

a work table having a slot therein;

means securing said work table to said machine table in a position inwhich said slot is disposed beyond the surface of said machine table onthe side thereof adjacent said spindle and parallel to a plane normal tothe axis of said spindle with said table disposed with the surfacethereof parallel to said axis;

an arbor carried by said chuck;

a circular saw blade mounted on said arbor and normally interengagedwith said slot; and

a lower saw guard normally secured to said work table and surroundingthe portion of said saw blade below said work table.

2. An assembly as defined in claim 1, wherein said machine is a drillpress having a shaft operative to move said spindle axially thereof,said shaft extending parallel to a plane normal to the axis of saidspindle and traversing the plane of the top of said work table, saidshaft having a disconnectable joint below said work table plane whensaid power head is placed below and adjacent saidplane.

3. An assembly as defined in claim 1, additionally including an uppersaw guard assembly having a splitter plate, said work table having asecond slot, said second slot being in axial alignment with said slotreceiving said saw blade and receiving said splitter plate.

4. An assembly as defined in claim 3, additionally including a bridgemember normally fixed to said lower saw guard and secured to said tableon opposite sides of said second slot.

1. In combination with a machine having a column, a power head securedto said column and having a spindle carrying a chuck and rotatable on anaxis parallel to said column, a table bracket adjustably mounted on saidcolumn, a table adjustably secured to said bracket, and pivotal supportmeans for said column providing for placement of said column in selectedpositions between vertical and horizontal, said column being rotativelyadjustable about its own axis with respect to said pivotal supportmeans, a circular saw assembly comprising: a work table having a slottherein; means securing said work table to said machine table in aposition in which said slot is disposed beyond the surface of saidmachine table on the side thereof adjacent said spindle and parallel toa plane normal to the axis of said spindle with said table disposed withthe surface thereof parallel to said axis; an arbor carried by saidchuck; a circular saw blade mounted on said arbor and normallyinterengaged with said slot; and a lower saw guard normally secured tosaid work table and surrounding the portion of said saw blade below saidwork table.
 2. An assembly as defined in claim 1, wherein said machineis a drill press having a shaft operative to move said spindle axiallythereof, said shaft extending parallel to a plane normal to the axis ofsaid spindle and traversing the plane of the top of said work table,said shaft having a disconnectable joint below said work table planewhen said power head is placed below and adjacent said plane.
 3. Anassembly as defined in claim 1, additionally including an upper sawguard assembly having a splitter plate, said work table having a secondslot, said second slot being in axial alignment with said slot receivingsaid saw blade and receiving said splitter plate.
 4. An assembly asdefined in claim 3, additionally including a bridge member normallyfixed to said lower saw guard and secured to said table on oppositesides of said second slot.